Artificial grass mat and method of making same



E. M. ELDER April 25, 1950 ARTIFICIAL GRASS MAT AND METHOD OF MAKING SAME Filed March 24, 1949 FIG. 2

FIG. 4

i 'atenteci Apr. 25,

ARTIFICIAL GRASS MAT AND METHOD or MAKING SAME Emil M. Elder, Shaker Heights, Ohio, assignor to The Joseph M. Stern Company, Cleveland, Ohio, a corporation of Ohio Application March 24, 1949, Serial No. 83,109

8 Claims.

My invention relates to artificial grass mats of the type used for decorative purposes in indoor exhibitions and for covering freshly turned earth as in cemeteries at new graves.

The attractiveness and general utility of artificial grass mats of this type depends to a large extent upon their effective simulation of the appearance of actual grass sod. The attainment of this appearance constitutes one of the major problems in the construction and fabrication of these mats.

In the past, grass mats have been made by cutting long strands of a suitable fiber, for example rafiia, to a uniform length prior to stitching them to a flexible fabric base or backing, such as burlap. In the manufacture of one form of prior mat the cut fibers are kept in parallel relation and fed onto a backing immediately ahead of the needle of a suitable sewing machine to form a row with the individual fibers extending substantially at right angles to the stitch line. As each row of fibers is thus secured to the backing the operation is repeated by stitching another row of fibers parallel to the preceding row in overlapped or shingled relation thereto and so on until the mat is covered by a series of parallel rows. In some cases two layers of rows of fibers are applied with the rows of the top layer extending transversely of the rows of the bottom layer.

When a mat of the type just described i bent around a corner or spread over an irregular surface the rows tend to open up and expose the backing and/or give an undesirable appearance of parallel rows which destroys the desired realistic grass appearance. In addition, the prior mat construction as above described is relatively expensive as it requires a large number of individualstitching operations in order to secure the rows of fibers to the backing.

I have overcome these defects and disadvantages by employing a method of fabrication which results in a product that is natura1 in appearance, sturdy in construction, and will neither expose the fabric backing nor assume a row-like appearance when bent around a corner. In making my improved artificial grass I preferably employ a multiple-needle sewing machine having a plurality of spaced needles operably mounted over a suitable work support which may include conveyers and feed rolls as required. I also preferably employ a suitable mechanical spreading device, disposed ahead of the multiple-needle sewing machine, with which to spread substantially uniform lengths of grass-like fibers, such as rafiia, onto one surface of a flexible fabric base that is disposed on the work supporting surface of the stitching machine. As the fabric base is caused to move under the stitching needles, the fibers are distributed thereupon by the spreader ahead of the needles in substantially horizontal random relation in the proper depth to give the particular quality of grass-sod wanted. The fibers are first stitched to a long continuous strip of the backing (as much as several hundred yards in length) in parallel lines as the strip moves under the spaced stitching needles. This material i then cut into mats of the desired length and the stitching operation is repeated on each mat by moving it under the row of needles in a direction transversely of the first set of stitch lines. By this procedure, as will more fully appear later, all fibers will be firmly secured to the backing.

As will be more fully explained later, the spacing between stitching needles, and consequently between stitching lines or rows, is preferably less than the length of the individual fibers, for example about one-half the fiber length. This relation between fiber length and spacing between stitch lines insures that each fiber will be firmly stitched to the backing at least at one place while permitting enough free ends of the fibers to stick up to give the desired appearance of natural grass.

Therefore, an object of my present invention is economically to produce a natural appearing imitation grass mat by mechanical means re.- quiring a minimum number of operations and manipulations.

Other objects of my invention include: the pro.- vision of an artificial grass mat in which sub-.- stantially all of the individual fibers are firmly secured to a flexible base, thus eliminating loosening and shedding of the same in use; the provision of an imitation grass mat whose grass-like pearance when the mat is curved, thereby greatly 2 is a plan view of a portion of the mat showing the disposition of the grass-like fibers thereupon after the first stitching operation; Figure 3 is similar to Figure 2 but show a portion of the mat after the second stitching operation; Figure 4 is a schematic representation of the disposition of some of the fibers on the flexible base, showing the preferred relation between the length of the fibers and the width of the spacin between rows of stitching; and Figure 5 is an enlarged vertical cross sectional view taken substantially on the line 5--5 of Figure 4.

Referrin to the drawings, and particularly to Figures 3, 4, and 5, my artificial grass, rnat coinprises a flexible fabric baseJorzbacking l ,,su ch .as burlap, and a layer of grass-like fibers 2, such as rafiia, disposed in a random relation to each other and to a suitable depth thereon to obscure said base I from the eye of an observer and .give ,the appearance of the desired type of grass sod. The fiber 9. rafiiaa r era Substant l 7 i inl esib a "w l be x l ned mo fully late '{Ihe n at alsoincludes stitch lines 3 and i which eXteIldacrQss-the layer of grass fibers 2 and downwardly'intoand through the base ,I and secure t e grass fibers to the flexible base. The fibers @are secured to the-base by .a pattern of stitches that tte i lus e ieFism' s 3 a 4 w re the stitch lines 55 and d are represented by dotted lines. .Qne set ofparallel stitch lines 3 runs the E E- il o t e ras m r ll' i 2) d the her ,set of parallel stitch lines e runs transrselyloi theffirs't's'et'(seeFigure 3). Thegrass- V f bers are thus secured to the fabric base by amiss-cross pattern of stitch lines forming adjacent parallelograms and preferably but not necessa'rilyhaving uniform spacingbetween adj acent paeua An important feature of my invention is the relation between the spacingiindicated at in Figures 2 and 3) of adjacent parallel stitch lines 3 "and 3 and the lengths of the individual grasslikefibers 2. The length of each-individual fiber preferably greater tha-nthe spacing and also greater than themaximum diagonal dimensions of the 'parallelograms (which are rectangles as illustrated) formed-by the intersecting stitch lines 3 and t. As-shown, -the fibers 2 are about twice the width of spacing 5. As is clearly seen in Fig.- u're l, this -relation:between.the lengthoffibers 2 and :the spacing between stitch lines 3 and 1% insures that :substantiallyevery individual grassilike fiber will be secured .to the base 1 .by oneor more of the stitch lines 3 or 4. For example, referringto Figure .4, strands 2a, 2b, and Zcare showndisposedsubstantiall rparallel to the stitch lines A andaresecured to thebacking I by stitch lines 5. In like manner, strands 2d, 2e, and 2] arasubstantially.parallelto thestitch lines 3 and are-secured to backing .l atone or more pointsby :the stitch lines it. Other fibers or strands shown insEfigure 4 are arranged in various other angular relations with respect to .the stitch lines and, as will be noted, are likewise secured to the base I atoneor morepoints by said stitch lines.

{The partial length of each strand or fiber 2 between an end thereof and the nearest row of stitches under which it extendsconstitutesafree portion of thatstrand which is available to prodcct upwardly from the base 1! in simulation of the upwardly projecting blades of grass. The length of these free end portionsof the strands .willyary as a resultpf the an i ua plurality of non-uniform upwardly-projecting blades of grass will be provided which give the appearance characteristic of natural sod. In some cases it may be desired to trim these upwardly extending ends to a substantially uniform height to give the appearance of a freshly mow-ed lawn. Example of such free portions ofrthestrands are designated in Figure 4by the characters 2g, 2h, 21', 27', 2k and 2m.

1 have found that my improved artificial grass mat may be manufactured by a much more economical andtime-saving method of construction than prior mats and that an exceptionally sturdy, wear-resistant andnatural-appearing mat is produced w ithr a In imum number of fabricating operations. .lnrel ligure l I have shown a portion of. a rr ultiple needle sewing machine including a support 6 over'whi'ch a plurality of needle guides i are supported by a suitable structure (not shown) and are alignedin a column. Projecting d wnwardl drain, th lowermos Portio of ea g ide ,a'i'stitchingneedle 8. These needles areof su bie sewing machinetypeand as they are not claimedassiiohil havelchosenlto represent them schematically. When the sewing machine is caused ,to operate all of the needles 8 wil function simultaneousl 'iihegne'e dles 3 are preferably but not necessarily uniformly spaced from. eachlotherand asufiicient nurnberare preferabl p to insure thatthe column of needles will extend across'thefull width of the fabric base sothatthe respectiv stitching line d c e h-side e g c the ase will be spacedjtherefroin a distance less thanthe ,spacing between adjacent needles. This .is clearly shown in Figures? and? .Wherein 13a and I l-d design te respectively the longitudinal and transverse stitching jlines' adjacent the sides of fabric base.

To startmanufactur .Q my, improved ma the end o'flajst'ri of fabric base material is dispo ed onl h fi i n l' com x rt, see Fi ure ,1, a a of ,thecjolumn ofstitching needles' .8. A suitable ut mat clmecha icalfi e -s eadin de i e n t sho s c asa ho pe equ ppe w t fe r0115 arranged t sprea the bers u rm y to the desi ed depth o t eibur apibackine. i positioned ab v h bac in su po t qn ev r and u sta all pa al to and ahea of h 'Q of needles 3. As the leading edged of the base 'I is moved under the needles 8 in the directionindicated by the arrowin Figure 1 the automatic spreader distributes grass like fibers in substantially horizontal random arrangement onto the base 'I to a depth sufiicient'to proyide'the desired cover. When the ends of the, coveredfabricbase reaches the row of stitching needles 8 the layer 0f proinisouously spreadfibers is stitched to the base by i etof parallel stitch lines '3 extending the ul Widt h m Thesswed at r then passes through talgeeoffrolls fi" which assist ic g ins the rip ugh h sewin mac i after he ab veidcsc b se isc tin o ndividua matslqf the-des red l ngth th lne s wing operation is .periorn edoneach mat. This operation is similar to thecne described above except that the needles .58 ,are caused .to stitch across the base l".transversely of the first set of stitch lines Sfarid thefiber distributing apparatus 1S not operated to spread more fibers upon the base. {Ifhis second stitching operation catches all fibers which were not sjeweididown to the'b'aseby the firststit hin oper menace also restitches a on i er." i d tih th r aileh by th first =$ii i i 1 i2 efiba Flt fsi ely i u e sous spreadin thereof -.l I 9. I theba L and thu 5 tha caebr ber b q llteds n one or igate places to the backing fabric. Figure 3 shows the mat after this second stitching operation.

The number of operating needles 8 on the stitching machine may vary according to the width of the mat to be sewn; that is, there preferably should be a sufficient number so that the needles at the ends of the row will stitch in lines that are spaced'from the edges of the base I a distance less than the spacing 5 between needles.

After the grass-like fibers 2 have been stitched to the flexible fabric base I in the manner above described, the free ends of the fibers are lifted up to give a nap to the mat by brushing as well as through agitation in the dye bath by which the mats are given the desired color. Since the free ends of the fibers will vary in length, as explained above, the upwardly projecting portions of the fibers will likewise vary somewhat in length and will give an appearance to the mat that closely simulates that of natural grass (see Figure 5). As also noted above the grass blades may be trimmed to the desired height.

My grass mat construction affords an opportunity to use a multiple-needle sewing machine and a mechanical spreader for the grass-like fibers, thus effecting great savings in operator time and cost of production. To the observers eye when viewing my improved mat the texture of the grass is uniform and full both when the mat is fiat and when spread over a curved surface.

My improved procedure provides, in a single operation, the depth of grass-like sod needed to cover the base and effectively obscure same from the observers'eye. The length of my individual fibers (greater than the diagonals of the figures formed by the intersecting stitch lines) that are spread in random arrangement upon the base insures the firm attachment of each fiber to the base and the cross-stitching of the layer of fibers insures that the flexible fabric base will be completely covered at all times and that the fibers will not have the undesirable appearance of parallel rows, common to prior mats of the type described, when the mat is bent around a corner.

The free ends of the fibers also cover and obscure the stitching rows thereby enhancing the natural appearance of the mat.

Although I have described the illustrated embodiment of my invention in considerable detail it will be understood that variations and modifications may be made in the form and arrangement of my improved artificial grass mat and in the method of making same. Furthermore, although the stitch lines of each set are shown as mutually perpendicular to each other, the transverse stitch lines could be disposed in other than a perpendicular relation to the longitudinal stitch lines. I do not, therefore, wish to be limited to the particular grass mat structure and method of making same herein shown and described but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

1. The method of fabricating an artificial grass mat comprising distributing a plurality of fibers of grass-like material upon a flexible fabric base in random relation to each other, said fibers being applied to said base in a single layer to a depth sufficient fully to conceal said base, stitching said layer of fibers to said base by a set of simultaneously formed parallel stitch lines spaced apart a distance less than the length of said fibers, again stitching said fibers to said base by a second set of simultaneously formed par-allel stitch d lines extending transversely of said first named set of stitch lines and spaced apart the same distance as said first set of stitch lines, and brushing said mat to raise the free ends of said fibers.

2. The method of making artificial grass or thelike comprising distributing grass-like fibers of substantially uniform length in random arrangement to a substantially uniform depth on a fabric base, simultaneously stitching said fibers to said base by a plurality of parallel stitch lines spaced apart a distance less than the length of said fibers, and then again simultaneously stitching said fibers to said base by a plurality of parallel stitch lines spaced apart a distance less than the length of said fibers and extending transversely across said first mentioned stitch lines.

3. The method of making artificial grass or the like comprising distributing grass-like fibers of substantially uniform length in single layer random arrangement to a substantially uniform depth on a fabric base, simultaneously stitching said fibers to said base by a plurality of parallel permanent stitch lines spaced apart a distance less than the length of said fibers, and then again simultaneously stitching said fibers to said base by a plurality of parallel permanent stitch lines extending tranvsrsely across said first mentioned set of stitch lines.

4. The method of making artificial grass or the like comprising distributing grass-like fibers in single layer random arrangement to a substantially uniform depth on a fabric base, simultaneously stitching said fibers to said base by a plurality of parallel permanent stitch lines spaced apart a distance less than the length of said fibers, and then again simultaneously stitching said fibers to said base by a plurality of parallel permanent stitch lines extending transversely across said first mentioned set of stitch lines, the minimum length of said fibers being greater than the maximum diagonal dimension of the parallelograms formed by said stitch lines.

5. An artificial grass mat comprising a flexible fabric base and a plurality of grass-like fibers secured thereto in single layer random relation by two sets of permanent stitch lines, the lines of one set extending transversely across the lines of other set, the spacing between the adjacent stitch lines of each set being approximately onehalf the length of said fibers.

6. An artificial grass mat comprising a flexible fabric base and a plurality of grass-like fibers of substantially uniform length secured thereto in single layer random relation by two sets of parallel stitch lines, the lines of each set being equally spaced from each other and the lines of one set extending transversely across the lines of other set, the spacing between adjacent parallel stitch lines being less than said uniform length of said fibers.

'7. An artificial grass mat comprising a flexible backing sheet completely covered on one side by grass-like fibers of substantially equal length disposed in random arrangement and secured to said backing sheet by two intersecting sets of parallel stitch lines, said intersecting stitch lines forming a pattern of adjacent parallelograms, and substantially all of said fibers being longer than the longest diagonal dimension of one of said parallelograms but shorter than twice said diagonal dimension.

8. An artificial grass mat comprising a flexible backing sheet completely covered on one side 7 8 singledayer of random gl ass-like flbgrs oj 7 REFERENCES CITED substantially equalh" intersecting of: The following references are ofrecord'in the 333 3ii iifi iiifiiffi ifid fii $21332; Of patent substantial-number of; said fibers bei n g secured 5 UNITED STATES PATENTS to, said backing at spaced points alqng their Numbep Name Date length by-two onmore of said s titch lings 1, 96 l 139- Elder June 5, 1934 EMI-L M} ELDER. 2,040,611 Kaderbeck May 12, 1936 

